Anchorage of continuous fiber-reinforced polymer strands

Abstract

In an anchorage (1) of continuous fiber-reinforced polymer (CFRP) strands that anchors continuous fiber-reinforced polymer strands (2) to concrete structures, there is provided an untwisted diameter-expanded portion (3) expanded to a diameter D2 by being radially expanded with respect to a diameter D1 of a general portion (4) of the CFRP strands (2) by untwisting any section of the CFRP strands (2) formed by stranding a plurality of element wires (20, 21) that are bundles of multiple continuous fibers, and filling and curing a time curable material (5) in a clearance among the element wires the untwisted section that is untwisted.

The invention claimed is: 
     
       1. An anchorage of continuous fiber-reinforced polymer strands, comprising:
 a continuous fiber-reinforced polymer strand formed by stranding a plurality of element wires that are bound together multiple continuous fibers in a first direction; and 
 a single or a plurality of untwisted diameter-expanded portions radially expanded with respect to a diameter of a general portion of the continuous fiber-reinforced polymer strand, the single or plurality of untwisted diameter-expanded portions being reversely stranded in a direction reverse to said first direction, the single or plurality of untwisted diameter-expanded portions being radially expanded by filling and curing curable materials in a clearance among the plurality of element wires, the general portion being other than the single or plurality of untwisted diameter-expanded portions of the continuous fiber-reinforced polymer strand, the single or plurality of untwisted diameter-expanded portions receiving bearing resistance by directly contacting at least one surrounding curable materials, selected from the group consisting of concrete, cement grout, and cement mortar. 
 
     
     
       2. The anchorage of the continuous fiber-diameter-expanded reinforced polymer strands according to  claim 1 , wherein said single or plurality of untwisted portions terminates at ends and wherein each of the ends has a cable tie so as not to be further untwisted. 
     
     
       3. The anchorage of the continuous fiber-reinforced polymer strands according to  claim 1 , wherein the single or plurality of untwisted diameter-expanded portions has a length that is at least five to twenty times the diameter of the general portion. 
     
     
       4. The anchorage of the continuous fiber- reinforced polymer strands according to  claim 1 , wherein the single or plurality of untwisted diameter-expanded portions has a maximum diameter that is at least 1.2 to 2.6 times the diameter of the general portion.